A variety of tools, systems, and assemblies require the supply of fluid or gaseous mixtures. For example, gas burners are utilized to generate a flame to heat a product using a gaseous fuel such as acetylene, natural gas, and/or propane, among other fuel sources. e.g., air-gas mixtures may be utilized as fuel for gas powered burners. In gas burners and other applications, the fluid may transition between different cavities, e.g., between conduits or pipes of different sizes, between a storage tank or area and a conduit or pipe, through a restriction or inlet, etc. Per fluid dynamic principles, it is generally known that transitioning between different cavities, e.g., differently sized cavities, can affect the pressure, velocity, and other characteristics of the fluid flow, which are herein referred to as entrance effects or transitional effects. Additionally, the flow may experience entrance effects along an “entrance length” proximate to the transition, with the flow stabilizing at some distance distal from the transition. Referring back to gas burners (particularly ribbon burners that are arranged to produce a flame along a length of the burner), the entrance effects introduced by the transition from the fuel inlet into the burner cavity can create an issue in which the properties of the produced flame proximate to the fuel inlet differ from the properties of the flame at distances further away from the fuel inlet.
Accordingly, there is a need in the art for an assembly for modifying the entrance and/or transitional effects of fluid flows in a reduced distance, such as for improving the operation of gas burners and other systems.